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Lens Molding and Molded Optics

Our engineers work closely with you to understand your application requirements, evaluate tolerances, establish quality metrics, and design and build a mold that will consistently produce optical elements to your specifications.

Advantages of Polymer Optics Over Glass Optics

  • Lower cost thermoplastics, such as PMMA (acrylic), cyclic-olefin polymer (COP), polycarbonate, polyesters, and polystyrene
  • Economies of scale from the injection molding process
  • Ability to produce complex shapes (aspheric and freeform optics) cost-effectively
  • Mounting features can be combined directly onto the optical element

Lower Material Costs

Thermoplastics are generally less expensive than glass. They are also made in very large volumes and are directly injected into the molding press in pelletized form. Unlike glass optics, thermoplastics are not pre-formed or shaped into a blank before injection molding.

Economies of Scale

In addition to being less expensive than glass, thermoplastics have a much shorter injection molding cycle time than the grinding and polishing techniques used to produce glass optics. Multi-cavity molds can also be built to produce multiple lenses during each molding cycle, which can further reduce costs for high-volume programs with commercial tolerances.

Complex Shapes

Aspheric surfaces can be added to optical systems to correct for geometric aberrations, such as spherical aberration, coma, astigmatism, and distortion. Complex shapes can be created at the optical mold insert and replicated many times during the injection molding process with excellent accuracy. Freeform optics are also becoming increasingly popular, particularly in AR/VR and HUD applications. The cost of producing freeform optics can be greatly reduced if the design can be optimized for injection molded plastics.

Combining Optical and Mechanical Features

Polymer optics can easily combine an optical surface with a mechanical mounting datum. This takes advantage of the manufacturing method of custom injection molding. By adding a mounting feature, such as a flange, tab, or other structure, the designer may be able to reduce the number of components in the final assembly and simplify the assembly process.

Polymer Optics Caveats

  1. Spectral transmission: most polymers are only suitable for visible or NIR ranges
  2. Constant service temperature level: lower than glass, generally less than 120°C
  3. High index of refraction temperature dependence (dn/dt): about 20x greater than glass
  4. High coefficient of thermal expansion (dl/dt): almost 10x more than glass

For solutions that require glass optics, please see our precision lenses page.

Product enquiry

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